1. Field of the Invention
The present invention relates to a control code read-out system, and more particularly to a control code read-out system which reads out a region code, which is one of control codes in a DVD playback apparatus.
2. Related Art
In the DVD-Video (Digital Versatile Disc) specification which is a video specification of DVD, a region code is used. In the prior art, as disclosed in Japanese Unexamined Patent Publication (KOKAI) No.11-143642, a control code read-out system has been used to change this region code.
FIG. 5 shows an example of the configuration of a control code read-out system of the above-mentioned prior art. This control code read-out system of the past has a region code storing section 9, a region code initialization mode switching section 5, for allowing initialization of the region code, a password interpretation section 4 that interprets a password of a prescribed bit length that is input from a local bus 2 and a local bus interface 3, a region code write section 6a, a region code read-out section 6b, and interface code interpretation section 7, which interprets an interface code that is input from the local bus 2 and the local bus interface 3, and a region code interface 8.
In this control code read-out system of the past, in the initialization mode, if the input password and interface code coincides with a password and interface code that are stored in the region code initialization apparatus 1, the region code is updated (initialized).
In the control code read-out system of the past, however, because protective measures of the region code such as encrypting are not provided, if the region code is stored in a file device, it is easy to decrypt the region code stored in the apparatus.
Additionally, because the control code read-out system of the past had no means for storing the number of changes of the region code, it was completely impossible for the user to change the region code.
Accordingly, it is an object of the present invention, in consideration of the above-noted drawbacks in the prior art, to provide a control code read-out system that can achieve access restriction by a region code, using only software.
It is another object of the present invention to provide a control code read-out system that can allow a user to change the region code.